Greg Hartman | 76d05dc | 2016-11-23 15:51:27 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License as |
| 6 | * published by the Free Software Foundation; either version 2 of the |
| 7 | * License, or any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, but |
| 10 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 17 | */ |
| 18 | |
| 19 | FILE_LICENCE ( GPL2_OR_LATER ); |
| 20 | |
| 21 | /** |
| 22 | * @file |
| 23 | * |
| 24 | * Line buffering |
| 25 | * |
| 26 | */ |
| 27 | |
| 28 | #include <stdint.h> |
| 29 | #include <string.h> |
| 30 | #include <stdlib.h> |
| 31 | #include <errno.h> |
| 32 | #include <gpxe/linebuf.h> |
| 33 | |
| 34 | /** |
| 35 | * Retrieve buffered-up line |
| 36 | * |
| 37 | * @v linebuf Line buffer |
| 38 | * @ret line Buffered line, or NULL if no line ready to read |
| 39 | */ |
| 40 | char * buffered_line ( struct line_buffer *linebuf ) { |
| 41 | return ( linebuf->ready ? linebuf->data : NULL ); |
| 42 | } |
| 43 | |
| 44 | /** |
| 45 | * Discard line buffer contents |
| 46 | * |
| 47 | * @v linebuf Line buffer |
| 48 | */ |
| 49 | void empty_line_buffer ( struct line_buffer *linebuf ) { |
| 50 | free ( linebuf->data ); |
| 51 | linebuf->data = NULL; |
| 52 | linebuf->len = 0; |
| 53 | linebuf->ready = 0; |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Buffer up received data by lines |
| 58 | * |
| 59 | * @v linebuf Line buffer |
| 60 | * @v data New data to add |
| 61 | * @v len Length of new data to add |
| 62 | * @ret len Consumed length, or negative error number |
| 63 | * |
| 64 | * After calling line_buffer(), use buffered_line() to determine |
| 65 | * whether or not a complete line is available. Carriage returns and |
| 66 | * newlines will have been stripped, and the line will be |
| 67 | * NUL-terminated. This buffered line is valid only until the next |
| 68 | * call to line_buffer() (or to empty_line_buffer()). |
| 69 | * |
| 70 | * Note that line buffers use dynamically allocated storage; you |
| 71 | * should call empty_line_buffer() before freeing a @c struct @c |
| 72 | * line_buffer. |
| 73 | */ |
| 74 | ssize_t line_buffer ( struct line_buffer *linebuf, |
| 75 | const char *data, size_t len ) { |
| 76 | const char *eol; |
| 77 | size_t consume; |
| 78 | size_t new_len; |
| 79 | char *new_data; |
| 80 | |
| 81 | /* Free any completed line from previous iteration */ |
| 82 | if ( linebuf->ready ) |
| 83 | empty_line_buffer ( linebuf ); |
| 84 | |
| 85 | /* Search for line terminator */ |
| 86 | if ( ( eol = memchr ( data, '\n', len ) ) ) { |
| 87 | consume = ( eol - data + 1 ); |
| 88 | } else { |
| 89 | consume = len; |
| 90 | } |
| 91 | |
| 92 | /* Reallocate data buffer and copy in new data */ |
| 93 | new_len = ( linebuf->len + consume ); |
| 94 | new_data = realloc ( linebuf->data, ( new_len + 1 ) ); |
| 95 | if ( ! new_data ) |
| 96 | return -ENOMEM; |
| 97 | memcpy ( ( new_data + linebuf->len ), data, consume ); |
| 98 | new_data[new_len] = '\0'; |
| 99 | linebuf->data = new_data; |
| 100 | linebuf->len = new_len; |
| 101 | |
| 102 | /* If we have reached end of line, trim the line and mark as ready */ |
| 103 | if ( eol ) { |
| 104 | linebuf->data[--linebuf->len] = '\0'; /* trim NL */ |
| 105 | if ( linebuf->data[linebuf->len - 1] == '\r' ) |
| 106 | linebuf->data[--linebuf->len] = '\0'; /* trim CR */ |
| 107 | linebuf->ready = 1; |
| 108 | } |
| 109 | |
| 110 | return consume; |
| 111 | } |